The present disclosure relates to a self-retaining contact lens for observation and surgical treatment of the vitreous or retina of the eye, and more particularly for use in vitreoretinal surgery.
Anatomically, the eye is divided into two distinct parts—the anterior segment and the posterior segment. The anterior segment includes the lens and extends from the outermost layer of the cornea (the corneal epithelium) to the posterior of the lens capsule. The posterior segment, which is much larger than the anterior segment, includes the portion of the eye behind the lens capsule. The posterior segment extends from the anterior hyaloids face to the retina, with which the posterior hyaloid face of the vitreous body is in direct contact, and further to the choroid and the posterior sclera.
The posterior segment includes the vitreous body, which is a clear, colorless, gel-like substance. The vitreous body gives the eye its globular shape and form, and comprises approximately two-thirds of the total volume of the eye. It is composed of 99% water and 1% collagen and sodium hyaluronate. The anterior boundary of the vitreous body is the anterior hyaloid face, which touches the posterior capsule of the lens, and the posterior boundary of the vitreous body is the posterior hyaloid face, which is in contact with the retina. The vitreous body, unlike the aqueous humor in the anterior chamber, is not free-flowing and has normal anatomic attachment sites. These sites include the optic nerve head, the macula lutea, the vascular arcade, and the vitreous base, which is a 3-4 mm wide band that overlies the ora serrata. The vitreous body's major functions are to hold the retina in place, maintain the integrity and shape of the globe, absorb shock due to movement, and to give support for the posterior aspect of the lens.
In contrast to aqueous humor, the vitreous body is not continuously replaced, and it becomes more fluid with age through a process known as syneresis. Syneresis results in shrinkage of the vitreous body, which can exert pressure or traction on its normal attachment sites. If enough traction is applied, the vitreous body may pull itself from its retinal attachment and create a retinal tear or hole, which may necessitate surgical repair.
Vitreoretinal surgical procedures are used to treat many serious conditions of the posterior segment, including age-related macular degeneration (AMD), diabetic retinopathy, and diabetic vitreous hemorrhage, macular holes, retinal detachment, epiretinal membrane, cytomegalovirus (CMV) retinitis, and many other ophthalmic conditions. When performing surgery of the posterior segment of the eye, as in vitreoretinal surgery, it is typically necessary to view the anatomy of the eye with an operating microscope and an ophthalmoscopy lens designed to provide a clear image of the posterior segment. Generally, a standard operating microscope is able to view the structures of the anterior segment of the eye and the anterior portion of the posterior segment of the eye, but cannot adequately view the entire posterior segment of the eye because the natural optics of the eye (i.e., the cornea and the lens) prevent the operating microscope from focusing on some structures in the posterior segment of the eye (e.g., the retina). Therefore, in order to focus the operating microscope on structures such as the retina, an ophthalmoscopy lens with appropriate optical properties may be positioned between the eye and the microscope to compensate for the natural optics of the eye.
The surgeon may make several tiny incisions (e.g., approximately one millimeter in length) in the sclera at the pars plana. The surgeon inserts microsurgical instruments through the incisions, such as a fiberoptic light source to illuminate inside the eye, an infusion line to maintain the eye's shape during surgery, and various instruments to cut and remove the vitreous body (e.g., a vitrectomy probe) or to manipulate tissue such as membranes or the retina itself.
Direct ophthalmoscopy lenses which create a virtual image within the eye and indirect ophthalmoscopy lenses which create a real image outside of the eye are two lens types which have been used for observation of the posterior segment and as aids in the surgical treatment of the eye. Known lenses that are used in vitreoretinal surgery may suffer from less than desirable image quality due to loss of contrast and sharpness secondary to various optical phenomena, such as, by way of non-limiting example, defocusing, spherical aberration, coma, distortion, and chromatic aberration.
The devices and systems disclosed herein overcome one or more of the deficiencies of the prior art.